1998 Fiscal Year Final Research Report Summary
Studies on the development of a system for effective calf production by in-vitro fertilization
| Project/Area Number |
08556046
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Applied animal science
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| Research Institution | Okayama University |
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Principal Investigator |
NIWA Koji Fac.Agr.Okayama University Prof., 農学部, 教授 (40089115)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAKE Masashi Kobe Univ., Fac.Agr.Assoc.Prof., 農学部, 助教授 (60093316)
KASAI Magosaburo Kochi Univ., Fac.Agr.Prof., 農学部, 教授 (60152617)
TSUNODA Yukio Kinki Univ., Fac.Agr.Prof., 農学部, 教授 (80217364)
MIYAMOTO Hajime Kyoto Univ., Fac.Agr.Prof., 農学部, 教授 (00026618)
OKUDA Kiyoshi Okayama Univ., Fac.Agr.Prof., 農学部, 教授 (40177168)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Bovine / Oocyte / In-vitro maturation / In-vitro fertilization / Frozen storage / Nuclear Transplantation / Theca cell / Plasmiongen activator |
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| Research Abstract |
The present study was conducted to develop an effective system for calf production by in-vitro fertilization. The results obtained from a series of experiments are as follows : 1) Epidermal growth factor (EGF) enhances not only nuclear maturation but also cytoplasmic maturation of cumulus-enclosed bovine oocytes, and thereby in-vitro development of oocytes, after in-vitro fertilization is promoted ; 2) Sperm penetration into oocytes is maintained in a chemically defined medium contained either caffeine or heparin, but it is much promoted in the presence of both chemicals with or without glucose ; 3) Stimulatory effect of bovine growth hormone and insulin-like growth factor-i on oocyte maturation is induced via cumulus cells ; 4) Theca cells inhibit meiotic resumption of cumulus-enclosed oocytes but do not inhibit the development of germinal vesicles by which their nuclei are synchronized at the stage just before germinal vesicle breakdown. The meiosis is resumed when oocytes are freed from theca cells ; 5) Plasminogen activators (PAs), which are known to have various physiological roles in ovulation and fert- ilization, are produced by cumulus-enclosed oocytes during maturation in vitro being enhanced by EGF.However, oocytes themselves can produce only ulokinase-type PA when cultured with cumulus cells ; 6) Informations adaptable to bovine oocytes/embryos are also obtained from the studies on vitrification and nuclear transplantation of oocytes in experimental animals, on developmental culture of pig oocytes activated 'by partheno- genesis, and on a role(s) of oxytocin in the development of follicles.
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